medwireNews: The timing of sentinel node biopsy may be important in patients with cutaneous melanoma, suggest researchers who found a poorer outcome for patients who underwent the procedure quickly after primary tumour excision.

“[O]ur results raise important questions and the implication that early sentinel-node biopsy reduces melanoma-specific survival in patients, needs to be further and prospectively explored”, say Antonio Tejera-Vaquerizo, from Hospital Universitario Virgen de la Victoria/Universidad de Málaga in Spain, and co-workers.

“But, what is clear is that a delay in the procedure did not worse[n] the prognosis in any case.”

Multivariate analysis of data for 1963 patients, followed up for a median of 46 months,indicated that a delay of 40 days or less to sentinel node staging was associated with a hazard ratio (HR) for worse melanoma-specific survival of 1.7 compared with a longer delay.

Other factors altering survival included a Breslow thickness of 2 mm or more (HR=>3.7), ulceration (HR=1.6), and sentinel node metastasis (HR=2.9).

On further examination, however, the length of delay to sentinel node biopsy was only significant for patients who had a negative test result, with a significant HR of 2.6 for patients who underwent the procedure in 40 days or less compared with those who had a longer delay.

In addition, when patients were stratified by the presence or absence of histological regression, only patients with regression showed a reduction in melanoma-specific survival with a shorter delay to sentinel node biopsy, with a HR of 2.4.

“[I]t could be hypothesised that the immunosuppressive sentinel-node microenvironment would disappear following excision of the primary tumour, allowing the induction of an efficient antitumour-specific immune response over the following weeks”, the researchers write in the European Journal of Cancer.

“In this scenario, early removal of the sentinel node would prevent this response and be detrimental to patients.”

They add: “Accordingly, in the setting of the presence of regression in primary melanoma, which is supposed to be a sign of immune response against tumour, it was not possible to observe an effect in delay time.”